The overall rating reflects the current state of the app. It accounts for all app reviews but prioritizes the most recent ones.
The app works reasonably well for exporting some data that can't be exported any other way. However: really had a mess when I updated and re-imported. Sent a message to the support team ... haven't heard a peep from them since. So unless you want to scramble your data ... probably not a good product to do mass updates or any uploads.
It's really such an incredible surprise when things just work. Simple as that. TIE makes changing, updating and adjusting my inventory an absolute breeze. Even with a relatively small product line, I'm able to perform previously arduous tasks with total ease.